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ToolsHutchings, Matthew I., Crack, Jason C., Shearer, Neil, Thompson, Benjamin J., Thomson, Andrew J. and Spiro, Stephen (2002) Transcription factor FnrP from Paracoccus denitrificans contains an iron-sulfur cluster and is activated by anoxia: Identification of essential cysteine residues. Journal of Bacteriology, 184 (2). pp. 503-508. ISSN 0021-9193
Full text not available from this repository. (Request a copy)Abstract
The Paracoccus denitrificans transcription factor FnrP has been characterized using artificial FNR-dependent promoter-lacZ fusion plasmids in Escherichia coli. FnrP can activate both class I and class II FNR-dependent promoters in response to anoxia but shows a marked preference for the class II promoter, where the FNR binding site is centered at -41.5 with respect to the transcription start site. FnrP was found to be inactive in an iscS mutant in vivo, demonstrating a requirement for cysteine desulfurase activity to assemble an iron-sulfur cluster in FnrP. Accordingly, an iron-sulfur cluster could be reconstituted into the purified protein in vitro using cysteine desulfurase, ferrous ions, and cysteine. Thus, FnrP is a true orthologue of FNR from E. coli and switches on target genes in response to anoxia. Inactivation of FnrP by oxygen very likely involves the oxidative disassembly of an iron-sulfur cluster. Possible ligands for the iron-sulfur cluster were identified by substituting each of the seven cysteine residues with serine and characterizing the altered proteins in vivo. Four substituted proteins showed activities less than 5% of the wild type, and so identify the four cysteines (Cys-14, Cys-17, Cys-25, and Cys-113) that are most likely to be involved in cluster ligation. The effects of N-oxides, NO-releasing compounds and a nitrosating agent on FNR and FnrP activity were investigated in vivo using the reporter system. Both proteins are very sensitive to the inclusion of sodium nitroprusside (a source of NO+) in defined growth media but are only moderately sensitive to those sources of NO that were tested.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Biological Sciences Faculty of Science > School of Chemistry (former - to 2024) |
| UEA Research Groups: | Faculty of Science > Research Groups > Molecular Microbiology Faculty of Science > Research Groups > Organisms and the Environment |
| Depositing User: | EPrints Services |
| Date Deposited: | 01 Oct 2010 13:36 |
| Last Modified: | 24 Sep 2024 10:15 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/345 |
| DOI: | 10.1128/JB.184.2.503-508.2002 |
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